It is often necessary to lock or secure rotatable machine elements so that they are not unintentionally rotated or turned under the influence of vibrations or other movements to a position in which they do not fulfill their intended function. In the case of machine elements provided with edged portions, such as bolts and nuts, it is for this purpose previously known to use a locking or securing device comprising a locking or securing element in the form of a washer which is movable to a position, in which an opening formed in the locking or securing element receives the edged portion of the machine element under a firm engagement between the surfaces thereof and the portions of the locking or securing element defining the opening therein and which locking or securing element is adapted to be secured against turning at a point positioned at a distance from the opening.
However, the previously known locking or securing devices of this kind are either unsatisfactory with regard to their security or complicated with regard to construction and use and thereby unsatisfactory from the economical point of view.